This invention relates to a vehicle headlight comprised of a housing, a light-transmissive self-locking cover plate connected to the housing, at least one catch device constructed as an integral piece with one of the parts to be connected and sprung perpendicularly with respect to a direction of assembly of the cover plate and housing, and at least one projecting part that automatically engages behind the catch device, wherein the catch device that permits the self-locking connection of the housing and the cover plate has a first slip-interface surface.
German patent document DE 28 46 990 A1 discloses a headlight of this type. A front outer edge of a housing supporting a cover plate, which is formed as a saucer-type reflector, has a receiving area for receiving the cover plate. A sealing material is placed into the receiving area. One can use a molded or extruded sealing material inserted into the receiving area, an adhesive placed into the receiving area, or a permanently viscous sealing material. Catch devices are formed on an outside of the receiving area, distributed evenly along an entire circumference on the outer edge of the housing, and pointing in a direction of exiting light. The cover plate has projecting parts on its outer edge area which are directed radially outward with respect to an optical axis, fitting into an opening in the catch device. When the cover plate is positioned on the housing, its projecting parts slide along slip-interface surfaces of the catch devices. The catch devices are thus sprung radially outward with respect to the optical axis until they engage behind the projecting parts in a self-locking manner. A separation between the catch devices and the headlight is not so great as to be disturbing, but the cover plate can become loosened from the housing in an undesired manner, because only a very small end section of the projecting parts of the cover plate can engage in openings in the catch device, owing to a small spring deflection of the catch device.
German registered utility model 76 05 088 discloses a vehicle headlight wherein catch devices are formed at an outer edge of a cover plate, pointing in a direction in which the cover plate is assembled into position. A spring direction of the catch devices runs perpendicular to a radius of an optical axis. A laterally positioned end section of each catch device engages behind a projecting part of the housing, in a self-locking manner. When the cover plate is positioned onto the housing, the projecting parts of the housing slide along leading diagonal parts of the catch devices, until the catch devices engage behind the projecting parts, in a self-locking manner. In this design, the spring deflection of the catch device is very small owing to its short length and because of its broad lateral surfaces that run in the spring direction. Therefore, it is impossible to ensure that the cover plate is securely mounted on the housing.
It is an object of this invention to provide a vehicle headlight as described in the opening paragraph above, wherein a catch device extends outward from the headlight as little as possible, even when (a) a housing is quick and easy to connect by means of long slip-interface surfaces, (b) a spring deflection of the catch device is as small as possible so that material with low elasticity can be utilized, and (c) the cover plate and housing are connected together securely through extensive contact between the catch device and a projecting part.